The deadly dioxide exacerbates lung disease and related respiratory problems, and also reacts in the atmosphere to produce ground-level ozone, a major component of smog.

The EEA warned that poor air-quality levels were wiping two years off people’s lives in the most polluted cities.

It also emerged that the breach in Glasgow could result in a multi-million-pound fine for the UK, because government officials did not apply to the European Commission for an extension to meet the 2010 target.

Professor Jacqueline McGlade, EEA executive director, said: “European Union policy has reduced emissions of many pollutants over the last decade, but in many countries, air pollutant concentrations are still above the legal and recommended limits… [and] air pollution reduces human life expectancy by around two years in the most polluted cities and regions.”

The figures showed nitrogen dioxide levels in Glasgow were 46.3 microgrammes per cubic metre, above the legal European limit of 40mg/m3.

Environmentalists in Scotland renewed calls for a congestion charge in Glasgow to reduce the city’s “deadly and shameful”

nitrogen dioxide is causing health problems for people in Glasgow and bringing forward their deaths. It is killing people.

“A congestion charge for Glasgow has been proposed before and is working well in reducing pollution in London. I would like to see it introduced here.”

Scottish Green Party leader and MSP for Glasgow Patrick Harvie criticised a “culture of delay and inaction”.

He said: “At the heart of the solution is providing reliable, clean buses and trains and safer routes for cycling and walking. We need to see a much greater sense of urgency from councils and the government.”

The EC offered governments a chance to apply for an extension from 2010 to 2015. However the UK government, which also makes applications on behalf of Scotland, did not make a submission for Glasgow, or 15 other UK areas breaching the limit.

An EC spokesman warned: “The government did not apply for extensions for zones including Glasgow, which it projected would be compliant by 2020.”

Any legal action could lead to fines in the region of “tens of millions of pounds”, he added.

Glasgow City Council said it was reviewing its air quality

action plan, but was “unlikely” to introduce congestion charging.

The UK government confirmed it had not applied for an extension after consulting the Scottish Government.

A Scottish Government spokesman questioned the val­idity of the EEA figures. He said: “The methodology used in these statistics is unclear.”